The present invention relates to a method of forming a series of radiation-curable composition having uniformly consistent properties. In particular, the method of the present invention relates to a method of forming a series of radiation-curable compositions wherein the radiation-curable composition may be used for any one or more of a variety of uses including, for example, coatings on fiber optics and/or coatings which form part of fiber optic cable assemblies such as: primary, colored or uncolored outer primary coatings as well as other coatings including inks and matrix materials.
Radiation-curable compositions are formed from radiation-curable oligomers which are themselves reaction products of polymeresation reactions. These polymeric reaction products typically comprise a majority of the desired oligomer but may also contain other components including some unreacted and partially reacted components as well as other polymeric reaction by-products. In addition to the variation in the make-up of the reaction products, the reaction process itself is difficult to control and additionally introduces variation into the resulting reaction products.
Since these polymer reaction products are used as the oligomer component in radiation-curable compositions, the resulting properties of typical radiation-curable composition are widely ranging. Consequently, the specification ranges for commercial radiation-curable compositions at present in industry include relatively large ranges. Since these compositions can vary as much as 30% from a target value for a given property, it is necessary for production facilities that use such compositions to implement production control mechanisms designed to address these relatively large variations in the properties of the radiation-curable compositions.
Of course, any attempt to produce a series of compositions with tight control of one choosen property generally will adversely affect the control or the magnitude of other properties of the radiation-curable compositions. For example, a method of production that is able to provide a series of radiation-curable compositions having uniformly consistent parameters achieved by adding a component, for instance a chain transfer agent that sacrifices the cure speed of the composition, would be unacceptable.
In accordance with the present invention, there is provided a method of forming a series of radiation-curable compositions (e.g. R1, R2 . . . ) having at least one uniformly consistent property.
The process of the present invention involves forming a series of radiation-curable compositions wherein the radiation-curable composition may be useful for any one or more of a variety of uses including, for example, coatings on fiber optics and/or coatings which form part of fiber optic cable assemblies such as: primary, colored or uncolored outer primary coatings as well as other coatings including inks and matrix materials. The process involves (a) forming a pre-composition, (b) measuring an in-situ sample of said pre-composition to determine a property of the cured pre-composition and (c) adding at least one adjusting agent to form a radiation-curable composition (R1) and repeating this process (a)-(c) to form at least one further radiation-curable composition (R2) wherein said property value for each of said radiation-curable composition (R1) and said at least one further radiation-curable composition (R2) are each within a target value range for said property.